Disc drives are used as primary data storage devices in modem computer systems and networks. While very reliable, today's disc drives occasionally fail. In addition to causing computer system downtime, such disc drive failures can result in the loss of some or all of the data stored in the disc drive. Accordingly, disc drives commonly perform Predictive Failure Analysis (PFA) using Self-Monitoring Analysis and Reporting Technology (SMART), to predict disc drive failure caused by the gradual decay of electrical and/or mechanical components of the disc drive. The primary goal of PFA is to predict when disc drive failure is imminent to allow the data stored in the disc drive to be saved.
PFA is generally performed during the operation of the disc drive by monitoring key disc drive attributes that are indicative of the health of the disc drive. Additionally, PFA can be implemented by performing periodic self-diagnostic tests on the disc drive. Present methods of performing PFA in disc drives predict imminent disc drive failure based upon errors associated with a single attribute (e.g., read errors, write errors, seek errors, fly-height errors, etc.). In these methods, errors corresponding to the single attribute are monitored and compared to a threshold value. When the errors exceed the threshold, a warning of imminent disc drive failure is provided to the user.
It is critical that the PFA method utilized in the disc drive be sensitive enough to detect imminent disc drive failure. However, it is also important that the method not be overly sensitive to false indications of imminent disc drive failure. In other words, while it is important to correctly identify disc drives that are about to fail, it is also equally important to avoid falsely predicting an imminent failure when the disc drive is functioning properly.
For example, disc drives include a spindle motor that rotates one or more discs. Over time, bearings of the spindle motor contained in raceways wear and eventually produce a vibration or mechanical resonance during the rotation of the discs that can result in disc drive errors such as data writing errors or write faults, which can lead single attribute PFA methods to prematurely predict disc drive failure even though the disc drive is not approaching imminent failure.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.